Crystal plating chamber apparatus

ABSTRACT

An improved crystal plating device having a base containing a power circuit and an oscillating circuit. The base is provided with a chamber and has a sealed top enclosing the chamber. At least one pair of filament posts are fixed to the base and disposed within the chamber and in the power circuit. A filament is connected across the filament posts. A crystal holder is removably connected with the base. The crystal is held by the holder in the oscillating circuit. A pump is connected to the base to vacuum pump the chamber. Energizing the circuits will oscillate the crystal and evaporate the filament to plate the crystal and produce the desired frequency therefore. 
     Filament posts each comprising a hollow body having an insulating sleeve thereon are threadedly received on a member affixed to the base. A slot is provided in the body near the upper end with a spring biased pivotable lever, the filament being disposed within the slot. Pivoting the lever of the filament post sideways will permit engagement of the filament in the slot upon release of the lever. 
     Contact pins extending through the base into the chamber produce enhanced electrical contact with the crystal holder in the chamber to ensure superior operation of the oscillating circuit during the plating apparatus.

RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. Ser. No.194,078, filed on Oct. 6, 1980, now U.S. Pat. No. 4,367,579, which is acontinuation of U.S. Ser. No. 034,780 filed Apr. 30, 1979, now U.S. Pat.No. 4,236,487. This application is also a continuation-in-part of U.S.Ser. No. 369,401, filed Apr. 19, 1982, now U.S. Pat. No. 4,419,379,which is a continuation of U.S. Ser. No. 193,935, filed Oct. 6, 1980,now abandoned, which is a continuation of U.S. Ser. No. 034,780, nowU.S. Pat. No. 4,236,487.

This application is also related to U.S. Pat. No. 4,323,031 which issuedon a divisional application to U.S. Ser. No. 034,780, now U.S. Pat. No.4,236,487. The entire disclosures of all of the aforementionedapplications and patents are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an improved apparatus for the plating ofmaterial, and more particularly to the vacuum plating of crystals in acircuit board.

2. Description of the Prior Art

Crystals can be made to oscillate at a natural frequency, or byappropriate and selective plating, can be manufactured to oscillate at adesired exact frequency. With the increased importance of electronics inour daily lives, crystals have gained widespread use, particularly inthe form of circuit boards, often used as clock oscillators.

Depending upon how exacting the frequency is to be set, for plating ofclock oscillator crystals, the user will base coat the crystal to arough frequency, mount it on an oscillator circuit board, and finallycallibrate the completed circuit by means of plating additional materialon the crystal to tune the entire circuit as a whole.

In other plating operations, individual crystals can be plated in theapparatus. In those cases the crystal may be first base plated on oneside, or both sides before final plating, again on one or both sides. Inthe more accurate frequency work it is recommended to coat both sides ofthe crystal to avoid "spurs" which is the occurrance of random peakscaused by aberrations of unknown origin.

In the frequency range of the present invention, the fundamentals andovertones thereof have been tested to 200 Mega Hertz (MHz) and above andhave tested out with great accuracy of 2 ppm up to frequencies of atleast 180 MHz.

Prior to the invention of U.S. Pat. Nos. 4,236,487 and 4,323,031 toKaplan, of which this invention is an improvement thereon vacuum crystalplating was done in a bell jar in which the crystal had to be internallyloaded with tweezers into a special holder within the bell jar. Theentire bell jar was evacuated including the special holder for thecrystal. The vacuum was drawn through a narrow opening in the jar. Thevacuum was not as absolute as desired. The relative size of the vacuumequipment, the complexly shaped items that were within the vacuumchamber, and multiple insulated wires disposed inside the vacuumchamber, provided multiple surfaces to which air or other contaminantscould adhere. The presence of these contaminants, together with thedifficulties in removing them resulted in deficiencies in the platingprocess and resulted in deficiencies in the product produced.

Additionally, the internal loading of the crystals within the bell jarwas relatively time consuming and, therefore, expensive. Also, becauseof the size and shape of the vacuum equipment, much of the noble metalvaporized in the plating process never reached the crystals to becoated. Instead the metal was randomly deposited on the walls of the jaror surfaces of the crystal holder. Therefore, the plating process waslengthened and much of the metal used in the plating process wasineffectively used.

Additionally, the random depositing of conductive material within thechamber produced shorting or other electrical conduction problems.Further, the random depositing of the precious metals on the vacuumsealing surfaces such as "O" rings and mating surfaces causeddeterioration of these surfaces and therefore, resulted in vacuum leaks.

The randomly deposited noble metal was recovered by cleaning thesurfaces within the bell jar. However, because of the complexly shapedand relatively large surfaces the cleaning process was not as quick oreasy as desired. Such apparatus as these are exemplified by U.S. Pat.No. 2,765,765 to Bigler et al, U.S. Pat. No. 3,756,851 to Rennick et al,U.S. Pat. No. 3,864,161 to Thompson, and and U.S. Pat. No. 4,112,134 toBuynak et al.

To overcome most of these prior art problems, the aforementionedinvention of Kaplan was produced. Kaplan's device provided a crystalplating device which reduced the vacuum pumping time due to itsrelatively small vacuum chamber, enabled alignment of the crystal to beplated to be made externally of the vacuum chamber thus reducing theextent of alignment of the crystal within the vacuum chamber, provided aplating device which was relatively easy to clean, minimized the amountof time required for loading of the chamber, facilitated effective useof the noble metal, and had many numerous other advantages.

Often, however, it is desirable to plate crystals after they have beenplaced in a circuit on a circuit board. The aforementioned Kaplan'sdescribed device was incapable of accomplishing this withoutmodifications that were relatively impractical. Additionally, filamentshave been developed which were essentially a conductive filament striphaving a plurality of areas of noble metal attached to the strip. Thefilament holder described in Kaplan was cumbersome to use with such typefilament.

SUMMARY OF THE INVENTION

To overcome the aforementioned problems, the present invention directedprimarily to an improved device for plating crystals was developed. Asindicated previously, this is an improvement on the invention describedand/or claimed in U.S. Pat. No. 4,236,487 to Kaplan, the entirediscloseure of which is incorporated herein by reference. Broadly, theinvention comprises an improved crystal plating device having:

a base having a power circuit and means for an oscillating circuittherein;

a chamber formed in the base;

a sealed top enclosing the chamber;

at least one pair of filament posts fixed to the base disposed withinthe chamber and in the power circuit;

a filament connected across the filament post;

a crystal holder removably connected with the base; and

a crystal in the oscillating circuit and carried by the crystal holder;

the base adapted to be connected to a pump to vacuum pump the chamber sothat energizing the circuits will oscillate the crystal and evaporatethe filament to plate the crystal and produce the desired frequencytherefore: the improvement comprises: an improved crystal holder whichcan accommodate a crystal in a plug-in circuit board having a pluralityof circuit connecting prongs, and the crystal holder including a plug-inmeans for inserting the prongs of the circuit board in the oscillatingcircuit.

Additionally or alternatively, the improvement comprises a filament posthaving a hollow body and an insulating sleeve thereon, the body beingthreadedly reecived on a member affixed to the base, a slot in the bodynear the upper end, and a pivotable lever, adjustably spring biassed,the filament disposed within the slot, whereby pressing the leversideways will permit engagement of the filament in the slot upon releaseof the lever.

Accordingly, it is an object of the present invention to provide animproved crystal plating device which can securely and conveniently holda circuit board therein.

It is another object of the present invention to provide a device whichenables alignment of the crystal in the cicuit board to be plated to bemade external of the vacuum chamber.

It is another object of the present invention to provide a crystalplating device which can plate the crystal in a circuit board.

Another object of the present invention is to provide a crystal platingdevice for crystals in a ciruit board which minimizes the amount of timerequired for loading the circuit board in the chamber.

Still another object of the present invention is to provide a crystalplating device which enables easy and rapid replacement of filamenthaving thereon plating materials which are used for vaporizing.

Yet another object of the present invention is to provide an improvedcrystal plating device which extends the useful service life of thefilaments used while also maintaining superior electrical contact withthe filaments.

It is a further object of the present invention to provide a crystalplating device which can plate crystals in circuit boards of differentsizes.

It is an additional object of the present invention to provide a crystalplating device that does not require modification of the chamber to varythe size of the circuit board on which the crystal is incorporated andwhich is being plated in the chamber.

It is an additional object of the present invention to provide a methodfor plating crystals in a circuit board which enables alignment of thecrystals simply and without need of special tools.

Other objects and advantages will be apparent from the followingdetailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated in the accompanying drawing in which:

FIG. 1 is an exploded perspective view of the crystal plating apparatusof the present invention;

FIG. 2 is a top plan view of the crystal plating device taken along line202 of FIG. 1;

FIG. 3 is an enlarged bottom plan view of a filament post powerconnection;

FIG. 4 is an exploded perspective of the holder for the circuit board;

FIG. 5 is a partial sectional view of the holder in the open position;

FIG. 6 is a partial elevational view of the holder in the closedposition;

FIG. 7 is a perspective view of the holder and filament posts ready foruse; and

FIG. 8 is a sectional view of a filament post taken along line 8--8 ofFIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention as illustrated in FIGS. 1 through 8 show animproved crystal plating apparatus in which a circuit board (20) havinga crystal to be plated.

Referring to FIGS. 1 and 7, the circuit board (20) is plug connectedwithin a holder (22) which when in its closed position is inserted intoa slot (24) of a base (26) in communication with a chamber (28) in whichis disposed a pair of filament posts (30) on one side of the circuitboard (20). Across posts (30) is mounted a filament (60) having thereongold or silver areas (32).

Referring to FIG. 1, base (26) is connected at the open bottom of thechamber (28) via the manifold to a suitable pump (not shown) which mayhave a control valve. The top (33) of the base (26) has an annular "O"ring (34) which will seal against the top cover (36). The cover (36) hasa rim (31) which fits about the circular top (33) to snugly seal the topwhen a vacuum is applied to the chamber (28). The vacuum pumping time isrelatively short due to a low volume chamber and the use of a wide mouthopening at the bottom of the chamber (28).

Referring to FIGS. 1, 3, and 7, two separate and independent circuitsare run within the base (26). Referring to FIG. 1, circuit is made by apair of shielded wires (38) which are grounded at the base (26) at thewire feed-through retainer plate (42) connected to the base (26) by afastener (44). As shown in FIG. 7, each wire extends insulatinglythrough the base (26). The inner end of each wire (38) connects to alead pin (50) which extends partially into the slot (24) near itsbottom. There are two pair of shielded wires (38) connected to glass tometal seals (39) in feed throughs into the vacuum system permittingvarious optional contact arrangements.

Referring to FIG. 7, the holder (22) has a contact surface (52) disposedon each side of an insulated block (54) Prongs (58) from the circuitboard (20) containing the crystal are fitted into receptacles (56) inthe block (54). The leads (55) contact the appropriate prongs in thecircuit board to maintain a circuit through the crystal which is in thecircuit board (20). When the circuit board (20) is mounted in theinsulated block in circuit with leads (55), a series circuit will beformed running from wires (38) to pin (50), to contact surface (52),lead (55), and prongs (58) through the crystal, and then out the otherside wherein the components appear in reverse order.

For plating only crystals, The wires (38, 38) are connected to anexternal frequency oscillator (not shown) which incorporates the crystalin the oscillating circuit. When plating crystals on circuit boards(20), the circuit board and crystal often form a clock oscillatorcircuit. Since the circuit board (20) contains the oscillator, all thatis necessary is to connect the circuit via wires (38) to an externalfrequency counter (not shown). Any Other of the wires (38), (38) can beused to supply the power to the oscillator in the circuit board (20).The oscillator with the crystal is connected to a frequency counterwhich monitors the changes in frequency as the plating proceeds. It willbe understood that any conventional oscillation circuit and oscillatorcan be used in order to achieve the improvement of the presentinvention, and therefore, no specific details thereof have been setforth herein.

Referring to FIGS. 1, 3, and 7, the second circuit is the power circuit.The power circuit is connected to a suitable power supply (not shown) towhich the conductive filaments (60) are attached as shown. FIG. 7 isattached across adjacent filament posts (30), and the posts (30) areconnected in series with the last post grounded to the base (26) tocomplete the power circuit. Upon energizing the power circuit, a currentof about 30 amps and 5 volts is passed through the circuit and thefilaments (60) so as to vaporize the silver or gold or any other metalor other substance that is sought to be vaporized (32) thereon. Theseareas (32) are adjacent to the crystal in the circuit board (20) andwill be directed through the mask (62) (see FIG. 4) mounted in theholder (22) to be deposited upon the crystal in the circuit board (20)so as to plate the crystal. Because the current is high and the voltagelow, the only element that gets hot is the high resistance filament (60)and the areas (32) of silver or gold or any other metal or othersubstance that is sought to be vaporized thereon. The filament posts(30) are of much larger mass than the filaments (60) and will act asheat sinks to greatly reduce cycle time. The heat drawn into thefilament posts, will in turn be dissipated by the relatively massivesolid body of the chamber. The effectiveness of the heat sink willimmediately cool the filament and stop the plating process, therebyreducing excess depositing of material which results in "overshoot".

The crystal holder assembly (22) is illustrated clearly in FIGS. 4-6.The holder is comprised of an insulated block (54). Pivoted from thebottom of block (54), one one side of the block on pivot rod (48), is amask holder (72). Vertically aligned inwardly facing flanges (82) act asstops to prevent overswinging of the mask holder (72) and preventing thecontacting of the circuit board (20) by the mask holder (72). Alongitudinal channel (70) is provided on the same side of the insulatedblock (54), as the mask holder (72), and includes plug-in means forinserting a circuit board therein. The plug-in means are shown as aplurality of mating receptacles (56) for the prongs (58) of the circuitboard (20).

The other side of the insulated block (54) is provided with a secondelongated channel (78) into which the prongs (58) of the circuit boardproject and make contact with leads (55) which are relatively thick barsof conductive material positioned in grooves in the sides and back ofthe holder as shown in FIGS. 4, 5 and 6. Leads (55) connect to leads(52) which are also held in grooves in block (54) and which are muchthinner and made of a conductive material having some resiliency such asa copper strip. The ends of leads (52) are bent to form curled fingerswhich extend away from block (54), and make brushing contact withconnector pins (50) of leads (38). The curled finger configurationcombined with the resilience of the contact (52) insures that excellentcontact is made with the contact pins (50). As the block is lowered, thecurled fingers of contacts (52) will touch the pins (50) and will thenbe forced inward toward the block as it is further lowered into thechamber. Therefore, the spring forces of the contacts (52) hold themagainst pins (50).

Holder (22) will be lowered into the chamber until a lip (23) at the topof the holder engages the top of the chamber. Maintained in elongatedchannel (78) is a holding means (61) which is comprised of two plates(80) outwardly spring biased by springs (100) having channels (68)thereon which press against prongs (58) to securely maintain the circuitboard (20) in the holder (53). The holding means is secured to block(54) by two screws (64).

As shown in FIG. 4, there can be as many as four curved finger contacts(52) and associated connection (55) in each holder to contact up to fourseparate pins (58) from the circuit board (20). As shown in FIG. 4,positioned in mask holder (72) is circular mask (62). This mask is shownin FIGS. 4, 6, and 7, wherein a tapered nozzle (94) is eccentricallyformed to permit adjustment thereof to align the nozzle (94) relative tothe crystal in the circuit board (20) by turning the nozzle (94) (arrowsin FIG. 4). This mask is preferably used for final plating of thecrystal in the circuit board (20). The mask is made from a relativelypliable plastic material which can be easily press-fit and removed asneeded and replaced by other masks with different configurations asneeded.

The circuit board (20) will have its prongs (58) plugged into receptacle(56) when the mask holder (72) is in the open position, as shown forexample in FIG. 5. The holding means (61) is then placed in the secondelongated channel (78) by squeezing the spring biased plates (80)together and abutting the channels (68) against the prongs (58)projecting from the other side of the receptacle (56). The mask holder(72) is then closed by having the inwardly facing flanges (82) abutagainst channel (70). This presents a narrow profile for insertionwithin the slot (24) of the base (26), as shown in FIG. 1. As shown inFIG. 7, the contact surfaces (52) will electrically engage lead pins(50) so that when the oscillator is activated, the circuit will becompleted and the crystal in the circuit board (20) will oscillate toenable the plating process to proceed.

Referring to FIGS. 1-3, and 7, the slot (24) is formed in chamber (28)along a line parallel to shielded wires (38). Inwardly from the ends ofslot (24) and on opposite facing sides thereof are two pairs of cloverleaf apertures (108), one aperture of each pair being sized to receivean insulating sleeve (110) which fits around the filament post (30) andinsulates it from the base (26). The second filament post (30), of eachpair, is slidingly disposed within a smaller diameter opening to begrounded to the base (26). In the embodiment depicted only one pair ofposts (30) is utilized. Although, as shown in FIG. 2, power may besupplied to both pairs of posts by leads (102) and the holder (22)oriented in opposite directions.

The chamber (28) extends top to bottom of the base (26) and includes theclover leaf appertures (108) in communication with the slots (30).

Referring to FIGS. 1, 3, 7, and 8, the filament post (30) is part of afilament post assembly (112) which may include the insulating sleeve(110) and the filament (60) and insulated filament post holder (114)having a horizontal mounting flange (116) to which a mounting screw(118) passes to be threadedly received in a tapered hole in the base(26). This is shown in FIGS. 1 and 3. There is one holder (114) for eachpair of posts (30) is cut out of the chamber (28) in a contour to aidevacuation of the chamber.

The holder (114) has two vertical holes (124) central thereto throughwhich threaded member (118) extends to receive a mounting nut (128)holding connecting lead (130) to member (118). The strip (130) extendsbetween the post (30) to leads (102).

Referring to FIGS. 1, and 3, the first of the posts (30) is connected tolead (130) which is in turn connected to external power supply lead(102) that extends through a metal sleeve and is sealed at its inner endby an "O" ring (not shown) to prevent an air lead to the vacuum chamber28. Referring to FIG. 1, a retainer (138) having bifurcated end,positions the wire (102) within the sleeve and sealingly holds thesleeve within the feed-through bore (132) through the base (26). Theretainer (138) is held in position by a threaded fastener (140).

Referring to FIGS. 7 and 8, the filament post (30) is provided with abody (142) which is hollow and threadedly mounted on member (118). Thebody (142) is provided with slot (144) at its upper end. a lever (146)is biased sidewardly by a spring (148) entrapped therein by screw member(150). Spring (148) will normally urge lever (146) sidewardly so thatthe slot (144) is readily accessible by urging the spring in theopposite direction (FIG. 8 arrows).

Referring to FIG. 8, the insulated sleeve (110) has a cut out whichuncovers the slot (144) of adjacent facing filament posts so thatwhenever a filament (60) is to be connected the operator presses thelever (146) so that the end of the filament can be inserted in the slot(144). Releasing the lever (146) allows the spring (148) to force thelever (146) sidewardly to entrap the filament (60) end within the slot(144) and securely wedge it in the slot (144). Thus, the metal filaments(60) are easily and securely fastened between adjacent pairs of posts(30). The height of the posts (30) is set to correspond to the circuitboard size and location of the crystal and the opening in the mask (88).

Referring to FIGS. 3 and 7, the power circuit is provided with a powerlead (102) which is connected to a suitable source of power, making acircuit from lead (130) to post (30) to filament (60) to uninsulatedpost (30) which is grounded to the base (26) so as to complete thecircuit. When the power source is energized, after the holder (22) isassembled in the base (26) and a vacuum established in the chamber (28),the electrical current will heat the filament (60) and cause the noblemetal to be vaporized and the nozzle (94) of mask (88) will direct thevaporized metal to be deposited upon the oscillating crystal in thecircuit board (20) which is controlled by the oscillating circuitpreviously described.

Prior to performing plating operations, the chamber is thoroughlycleaned. This is accomplished by disconnecting the internal power supplyleads (102), removing the pairs of filament posts (30). The chamber andthe posts can be cleaned by any cleaning implement, as for example asmall brush. After cleaning, the apparatus is reassembled and connectedto the power supply and the external oscillator if necessary, or thefrequency counter. A filament, having thereon a noble metal, e.g.,silver or gold, is then placed in and connecting adjacent the filamentholders to complete the electrical circuit.

The chamber is then connected to an appropriate source of vacuum byplacing the chamber on top of a vacuum manifold, so that the vacuum canbe drawn from the bottom of the chamber. A circuit board containing acrystal to be plated is mounted within the holder (22) in preparationfor plating. Wide ranges of circuit board sizes can be accommodated inthe chamber for the different dimensions of the circuit boards and stillbring the crystals into proper location for plating.

One or more holders (22) can be used in the plating process. Preferably,several holders will be used to insure that the vacuum chamber will notbe idle while circuit boards are being mounted remotely of the chamberin holders for plating.

After the circuit board is placed in the holder, the cover of the holderis brought into upright position, bringing the mask into operativeposition with the face of the crystal in the circuit board. The mask ismanipulated to the position that will deposit the material in thedesired location of crystal in the circuit board.

By rotating the mask, it is possible to adjust the horizontal verticalposition of the eccentrically positioned orifice in the mask withrespect to the face of the crystal. As mentioned, different maskconfigurations can be used with the same holder.

The crystal holder (22) is then placed in the slot (24) of chamber (28)so that the contact surfaces (52) of the holder will make electricalcontact with the lead pin (50) from the external oscillator lead orfrequency meter or power supply network to the internal oscillator, ifone is used. The cover of the chamber is then put in place and is sealedautomatically as the vacuum is drawn from the bottom of the container.

When an internal oscillator is used, power is provided to the oscillatorto which the crystal in the circuit board is connected and incorporated.The frequency of the oscillator is accurately measured by a frequencymeter to which the oscillator is externally connected. Plating of thecrystal in the circuit board can be started once the crystal beginsoscillating. Plating is commenced by connecting the power supply to thefilament by an appropriate switch which has not been shown. The head inthe filament combined with the vacuum in the chamber vaporizes thesilver or gold on the filament and as the vaporization proceeds,particles of the vaporized material are deposited and condense on theunmasked portion of the crystal. The frequency of the crystal willchange as the buildup of the condensed material continues on thecrystal. When the frequency counter indicates that the desired frequencyis reached, the power to the filament is discontinued. Because of therelatively small size of the filament as compared to the filamentholder, and adjacent mass of the chamber, the heat will be rapidly drawnaway from the filaments, cooling them sufficiently to quickly andvaporization of the plating material. After plating has been completed,the vacuum is released and the circuit board holder is removed andanother holder is inserted for the next plating operation.

The ribbons containing plating material are easily positioned forplating in the filament posts as shown in FIG. 7. The filament is ribbonshaped and formed of a relatively thin strip of electrically conductiveand resistive material, such as tantalum, molybdenum, tungsten, etc.,which will heat upon application of current as previously described. Thefilament has been stretched or dimpled at an approximate mid-pointlocation.

The dimple acts as collecting reservoir for a candy can shaped sliver ofprecious metal or other plating material which is placed on the upperedge of the filaments and melts into a ball which "wets" into the dimpleunder the influence of surface tension, when power is initially appliedto the filament.

Many plating cycles can be completed without exhausting the ball ofplating material that has been formed in the dimple. The ball can bereplenished by merely placing additional slivers of plating material asneeded on the top of the filament. After numberous slivers have beenconsumed, the filaments will deteriorate and break. The filaments can beeasily replaced by merely pivoting the top of spring loaded lever (146)and inserting the new filament in slot (60).

It should be noted that (150) coacts with spring (148) to adjust thetension of lever (146) against filament (144). This tension is importantbecause it provides the contact pressure for proper conductivity and atthe same time should not be a source of excessive shearing pressureagainst the heated filaments, which produces premature failure.

It should also be noted that the filament post described willaccommodate less efficient straight wire filaments or a wide variety ofother filament shapes and sizes.

It should be noted that the interchangeability of masks and/or holdersallows for the plating of different size circuit boards in the samechamber without modifying the chamber in any way to accommodate thedifferent size circuit boards. Also, because the different masks can beused interchangeably, it is convenient to separately perform either basecoating or final calibration coating procedures in the same chamber.Further, if desired, because of the superior qualities of thisapparatus, it is possible to conduct both base and final calibrationprocedures during a single operation in the apparatus when coatingcrystals without their accompanying circuits. The single or one stepprocedure is used when the final product does not require theintermediate processing steps often employed to insure compliance withmore stringent crystal performance specifications.

From the above discussion it is clear that there are many advantages ofthe present apparatus. For example, the vacuum chamber (28) is ofrelatively small volume and is relatively uncomplicated in shape, andhas never been utilized in conjunction with the plating of a clockoscillator circuit board. By using the removable circuit board holder tomount the circuit board, all circuit board adjustments can be made inplaces remote from the vacuum chamber where there is adequate workingroom and where the process of adjusting the circuit board in the holderwill not interfere with the plating operation. After the plating hasproduced the build up of the plating material on the walls of thechamber, the unused plating material can be easily removed andrecaptured by the ease of cleaning the plating chamber.

The relative small volume of the vacuum chamber combined with the use ofthe holder to hold and adjust the circuit board prior to plating insuresthat the actual cycle time for performing the plating in each of thecircuit boards is relatively short. Additionally, almost all of thevaluable plating material can be recaptured without difficulty by thesimple cleaning process mentioned previously.

The purpose of the holding means (61), which is spring loaded, is tohold the prongs from the circuit board against the contacts to insureoptimum electrical continuity between the leads (55) and the prongs ofthe board so as to power the crystal circuit and thereby oscillate itduring the coating process so that it can be coded to the exact andprecise point that the frequency desired will be produced by the mask onthe crystal. This is done by having the two plates (80) which areresiliently urged apart by means of the two small springs (100), placedin tracks behind or in the back of the mask body. Dog-legs extendinginto the groove in the back of the mask can be compressed or squeezedtogether when the board is inserted into the corresponding receptacle tohold the board. The tension on the end of the springs is then relievedand the plates urged apart, the dog-legs, therefore, pressing all of theprongs extending from the chip to hold them fast against the sides ofthe back receptor to which the leads are connected.

It will be understood that the various changes in the details,materials, arrangement of parts and operating conditions which have beenherein described and illustrated in order to explain the nature of theinvention may be made by those skilled in the art within the principlesand scope of the invention.

What is claimed is:
 1. A crystal plating device comprising:(a) a basehaving a power circuit and means for an oscillating circuit therein; (b)a chamber formed in the base; (c) a sealed top enclosing the chamber;(d) at least one pair of filament posts affixed to the base disposedwithin the chamber and in the power circuit; (e) at least one of saidfilament post comprises a hollow body having an insulating sleevethereon and threadedly received on a member affixed to the base, a slotin the body near the upper end and a spring biased pivotable lever, thefilament disposed within the slot, whereby pivoting the lever willpermit the selective engagement and disengagement of the filament in theslot; (f) a filament connected across the filament posts, wherein thefilament posts are positioned in the chamber adjacent the crystal toprovide effective plating of the crystal; (g) a crystal holder adaptedto releasably support a crystal removably connected with the base; (h) acrystal in the oscillating circuit and carried by the crystal holder;and (i) said chamber adapted to be connected to a pump to vacuum pumpthe chamber, whereby energizing the circuits will oscillate the crystaland evaporate the filament to plate the crystal and produce the desiredfrequency therefore.
 2. A crystal plating device having:(a) a basehaving a power circuit and means for an oscillating circuit therein; (b)a chamber formed in the base; (c) a sealed top enclosing the chamber;(d) at least one pair of filament posts affixed to the base disposedwithin the chamber and in the power circuit; (e) a filament connectedacross the filament posts, wherein the filament posts are positioned inthe chamber adjacent the crystal provide effective plating of thecrystal; (f) a crystal holder adapted to releasably support a crystalremovably connected with the base; (g) a crystal in the oscillatingcircuit and carried by the crystal holder; and (h) said chamber adaptedto be connected to a pump connected to the base to vacuum pump thechamber, whereby energizing the circuits will oscillate the crystal andevaporate the filament to plate the crystal and produce the desiredfrequency therefore; wherein the filament post comprises a hollow bodyhaving an insulating sleeve thereon and threadedly received on a memberaffixed to the base, a slot formed in the body near the upper end and aspring biased pivotable lever, the filament disposed within the slot,whereby pivoting the lever will permit selective engagement anddisengagement of the filament in the slot.
 3. The plating device ofclaim 1, or 2, wherein said means for an oscillating circuit in saidbase comprise at least one contact pin extending through said base intosaid chamber.
 4. The plating device of claim 3 wherein said contact pinis constructed and arranged to be in resilient contact with saidoscillating circuit.
 5. A filament post for holding a filament in acrystal plating device comprising:(a) a member affixed in the platingdevice and in a power circuit; (b) a hollow body having an insulatingsleeve thereon and threadedly received on the member; (c) a slot in thebody near the upper end and a spring biased pivotable lever, wherebypivoting the lever will permit selective engagement and disengagement ofthe filament in the slot, wherein the filament posts are positioned inthe plating device adjacent the crystal to provide effective plating ofthe crystal.
 6. A crystal plating device comprising:a base having apassage extending from one end of said base to the other; one end ofsaid base with said passage adapted to be connected to a source ofvacuum; a cap adapted to coact with the other end of said base with saidpassage to seal said other end of said base, and with a source of vacuumseal said passage to form a sealed chamber within said base; means foroscillating a crystal in said base extending into said chamber; saidchamber adapted to receive a crystal holder adapted to releasablysupport a crystal in operative contact with said means for oscillating acrystal; at least two filament posts mounted in said chamber disposed tohold a filament in operative relation to said crystal holder, whereinthe filament posts are positioned adjacent the crystal to provideeffective plating of the crystal; at least one of said filament postscomprising:positioning means adapted to receive a conductive ribbon andoperatively position said ribbon with respect to said crystal holder;resilient means to selectively urge engagement or disengagement of suchfilament into electrical conductivity with a power circuit; a powercircuit extending into said chamber and connected to said filament postso that actuation of said power circuit will cause power to pass throughsaid filament post to a filament positioned in the post to vaporizeplating material or the filament.
 7. The plating device of claim 6wherein:at least one of said filament posts has a free end and; saidpositioning means comprises:a slot extending across said filament postand extending from the free end inwardly along the length of saidfilament post; means allowing rotation of said slot to position saidslot with relation to said chamber; stop means to limit the travel ofsaid lever.
 8. The plating device of claim 7 wherein said resilientmeans to urge said filament into electrical conductivity with said powercircuit comprise:a flat surface on said filament post; a lever pivotablyconnected to said filament post; resilient means to resiliently urgesaid lever against said flat surface on said filament post.
 9. Theplating device of claim 8 wherein one of said filament posts comprise::aconductive core; a conductive threaded member threaded into saidconductive core; an insulating sleeve disposed about said saidconductive core; a flat surface formed at one end of said conductivecore; slot means formed in said insulating sleeve; said insulatingsleeve extending around said lever means and the slot thereon disposedin registration with the flat surface of said insulating core; saidinsulating sleeve in register and serving as a stop means to limit thetravel of said lever.